Well, as to the manure pile, I don't know about the old stuff, but it wouldn't surprise me. But I can guarantee you that if they have access to the "fresh" stuff, they will scratch it down looking for goodies. This is actually how I came to have chickens. I was out raking down manure piles in the pasture, and commented to DH "If we had chickens they would do this for us". He went and got 6 hens and a few weeks later we went back and got the roo. They scratch down manure in the pasture and in the stalls.

Chickens LOVE manure. They are not hurt by pecking around in it because they have high acid in their stomach or something that keeps them from getting sick from it. They will pick apart manure to get at the larvae, bugs, seeds, etc in it which is just fine. Think about it, they have the perfect legs for wading through fresh cow patties and not getting their feathers dirty!

As for your other questions, the reason you keep chicks warm at first is because they are born with soft "down" and not feathers. Once their feathers grow in completely they don't need heat. (depending on whether you live in freezing temps and what breed you get). My adult RIRs and BOs don't need heat at all anytime of year and I'm guessing in Ohio you won't need to heat either.

My understanding is that chicks should be started with the heat lamp at a 95 F degree temp and reduce it 5 degrees each week after than until it's about the same as your outside weather.

I don't know if chickens are afraid of the dark, but they do need their sleep so when they're out of the brooder there's no need to put a light in their house. When they're chicks and you have the heat lamp on them, you can keep the light on 24/7 because they sleep frequently day and night anyways.

When you let them outside, if you are free-ranging them, you must consider if there are any predators in your area. if so you can search on here what others have done with cages, etc. to prevent predation.

It's best to merge chickens of the same size, so I'd wait until the chicks are grown.

Hope this answers some of your questions. The hardest part of raising chicks is the first 4-5 weeks. After that they're farily self sufficient and will get fat on your manure pile!

Backyard Chickens was my ONLY source of information when I got started on chickens a year ago. I've had little problems here and there, but every single one I solved with info from this site. My chickens are now huge, healthy, happy, and I haven't lost one yet (knock on wood).

They are pretty easy... but they can preoccupy you!

I think I put mine outside at four weeks because they were growing so much and I didn't have the brooder space. But I brought them in at night for a couple weeks and it was july by then, so pretty warm. If they're fully feathered, I wouldn't give them extra heat at all unless it dips below the 50's or so... when they're adults they only need heat if it's below 10.

The manure and compost is fine for them.

I wouldn't merge the two groups until the chicks are the same size as the hens so they don't get picked on.

My chicks were scared of the dark at first, but they got used to it pretty quickly.